Exhaust steam injector



Oct. 2, 1934. J. F. GRIFFIN EXHAUST STEAM INJECTOR Filed Jan. 2, 1931 II l l l l I I l l ll.

lNVENTOR Joseph F. Griff n BY 6. V,

ATTORNEY Patented Oct. 2, 1934 UNITED STATES EXHAUST STEAM INJECTORJoseph F. Griffin, Teaneck, N. J assignor to The Superheater Company,New York, N. Y.

Application January 2, 1931 Serial No. 506,106

.7 Claims. (01. 103-265) This invention relates to change-overmechanisms for exhaust steam injectors and other types of apparatus andaims to provide an ar-- rangement of greater reliability than that now 5mostly used.

Double pressure steam injector arrangements using live and exhaust steamhave been proposed adapted to automatically admit auxiliary steam fromthe boiler to the exhaust steam chamber of the injector whenever thepressure of the exhaust steam becomes insufiicient to maintainsatisfactory operation of the injector. An arrangement adapted tooperate in this way is disclosed in Patent #1,573,059, to Malcolm Hard.It has been found, however, in the operation of exhaust steam injectorsthat it is very difiicult to so design the exhaust steam nozzles thatthe injector will operate on as low a pressure of exhaust steam as isdesirable and will also prevent the jet' from breaking at the pressuresof exhaust steam occurring when the locomotive is developingits greatesthorse-power output. As the periods of maximum load on the locomotiveoccur much more infrequently than those of low exhaust pressure, exhauststeam injectors are ordinarily so designed that they cease to operateproperly at the maximum pressures of exhaust steam encountered inpractice.

It is an object of the present invention to pro- .vide a change-overarrangement for exhaust steam injectors and other devicesrequiring anauxiliary steam supply and adapted toavoid the difficulty just mentionedby automatically substituting a source of fluid of substantiallyconstant pressure for one of variable pressurejwhen the latter is toohigh.

In accordance with my invention, the exhaust steam injector or otherapparatus is maintained in operation when the exhaust steam pressuresare too high for use in the apparatus by auto- 1 matically substitutingfor the exhaust steam at such pressures the ordinary auxiliary steamsupplied from the boiler, heretofore used only when the supply ofexhaust steam has been either absent or abnormally low.

In order that myinvention may be clearly and easily understood, Iwillnow describe in detail, in connection with the accompanying drawing,a particular arrangement of an exhaust steam injector forming anillustrative embodiment of my invention. In said drawing,

Fig. 1 is an elevation of a locomotive having an exhaust steaminjectorattached theretoj Fig'. 2 is a vertical sectional view thru theautomatic valve appearing in Fig. 1 and used in accordance with myinvention for controlling the change-over from exhaust steam toauxiliary steam under conditions of excess pressures of exhaust steam.

Referring to the drawing more in detail, 10 is I the boiler of alocomotive and 12 is a steam pipe carried thereby and connected into thesteam space of said boiler for supplying steam to the ordinary auxiliaryjet and for the ordinary supplemental steam supply of an exhaust steaminjector 14. 16 is the engineer's valve in pipe 12 having a hand lever18 whereby the injector 14 may be thrown into and out of operation.Steam which has been exhausted from the engine cylin-' ders is suppliedto the injector 14 through a pipe 20 while the ordinary water supplypipe, overflow pipe and delivery pipe are indicated at 22, 24 and 26respectively. In the ordinary operation of injector 14, live steam forthe auxiliary jet is supplied from the boiler through pipe 12 andexhaust steam is supplied to injector 214 through the pipe 20. When,however, the exhaust pressure in pipe 20 falls below a certain point,the low pressure exhaust jets are unable to maintain the injector inoperation. and. auxiliary live steam must be suppliedtothe exhaust steamchamber of injector 14. For this purpose, an automatic change-overmechanism is ordinarily employed, one form of which is illustrated insaid patent to'I-Iard. The preferred arrangement, however, and the oneshown in the drawing, is similar to that disclosed in the patent ofMalcolm Hard, No. 1,870,006, August 2, 1932, reissued July 3, 1934,Re-issue No. 19,229,;for Exhaust steam injectors. In the arrangementillustrated herein, an automatic change-over valve will be understood tobe used within the casing 28, such valve being adapted to control theport for supplying auxiliary steam from the live steam pipe 12 into the9 exhaust steam chamber of injector 14 and also to control steam forclosing a valve for cutting oif the exhaust steam chamber of theinjector from the exhaust steam pipe 20 whenever. supplemental livesteam is being used. The action v of the change-over valve in casing 28will be'understood to be controlled by a relay valve also in casing 28,said relay valve being controlled in turn by a vent valve operated by avalve in the casing 30. The valve in casing 30 is controlled by a 9diaphragm the under face of which is subject ordinarily to the exhauststeam pressure in the pipe 20 by exhaust steam supplied through pipe 32having one end connected into the bottom of casing 30 and the other intothe pipe 20. Whenever the exhaust steam pressure against the under faceof the diaphragm in casing 30 falls below a given point, a spring in thecasing moves the diaphragm in such casing downward so as to produceconditions in the casing 28 causing the operation of the relay valve tosupply fluid to operate the change-over valve as above described. Itwill be understood that the foregoing description of the injectorillustrated in Fig. 1 relates solely to injectors of the prior artwhich, while forming part of my novel combination, are not in themselvesclaimed. herein, and it will be understood further that I do not limitmyself to the mechanism shown in either of said patents.

In accordance with my invention, if the pressure in pipe 20 reaches sucha point that there is danger the injector 14 will go out of operationdue to breaking of its jet, I vent the under surface of the diaphragm incasing 30 to atmosphere thereby producing such conditions in thechangeover mechanism as cause it to switch from exhaust steam operationto auxiliary steam operation. For this purpose, I place in the pipe 32 avalve casing 34 which is illustrated in detail in Fig. 2. In the formshown, valve casing 34 comprises a central chamber 36 connecting throughports 38 and 40 with the chambers 42 and 44 respectively, lying one oneach side of the chamber 36. Chamber 36 is connected directly with theunder face of the diaphragm in casing 30, while chamber 42 is connectedto the exhauststcam pipe 20, and chamber 44 is connected through thevent 46 with the atmosphere or otherplace of low pressure. A valve 48 isprovided at the inlet end of port 38 which is normally open, but whichisso arranged that when it is seated chamber 36 and diaphragm casing 30are cut off from the exhaust steam pressure. A normally seated valve 50is provided at the outlet of port 40 and so arranged that when it isseated, chamber 36 is cut off from the chamber 44 and from theatmosphere. Valves 48 and 50, however, are set in alignment and haveprojections 52 and 54 thereon arranged to contact and of such lengththat when valve 48 is seated, valve 50 is open and vice versa. Valves 48and 50 are acted on by springs 56 and 58 respectively which thrust inopposite directions. Spring 58 is made suificiently stronger than spring56 so that valve 50 is normally seated and valve 48 normally open. Theexhaust steam pressure from pipe 20 is therefore normally free to passinto the diaphragm casing 30 as previously described. When, however, thepressure in pipe 20 rises above a certain predetermined value, spring 58is no longer able to retain valve 50 on its seat against the combinedthrusts of the steam pressure and that of spring 56 so that valve 50opens connecting chamber 36 to the atmosphere through port 40, chamber44 and vent 46. Spring 56, assisted by the rapid flow of steam pastvalve 48,--this velocity having increased due to venting through chamber44 and vent 46thereupon promptly seats the'valve 48 cutting 01? thechamhaust steam pressure.

It will be seen also that the arrangement according to my invention hasthe further advantage of protecting the diaphragm in casing 30 againstabnormal pressures either steam or hydrostatic.

It will be understood also that I do not limit myself to any particularform of valve or type of mechanism for producing the conditions settingin motion the change-over mechanism when the exhaust steam pressuresreach abnormal value.

I claim:

1. The combination with an apparatus having a normal source of fluidsupply of variable pressure and an auxiliary source of fluid supply andhaving automatic mechanism for shutting off said normal supply and foropening up said auxiliary supply when the pressure of the normal supplyis below a predetermined minimum and adapted to restore connection tothe normal supply and to cut off the auxiliary supply when the pressureof the normal supply has risen above said minimum, said mechanismincluding a connection to said normal source of supply, of automaticmeans for venting said connection to a region where the pressure isbelow said minimum only when the pressure of the normal source has risenabove a predetermined maximum.

2. The combination as set forth in claim 1 and in which the ventingmeans isconstructed and arranged to out 01f the connection between theautomatic mechanism and the normal fluid supply at the time saidconnection is vented to the region whose pressure is below thepredetermined minimum.

3. The combination with an injector having a supply of exhaust steam andan auxiliary steam supply and having automatic mechanism for shuttingoff said exhaust steam supply and for opening up said auxiliary supplywhen the pressure of the exhaust steam supply is below a predeterminedminimum and adapted to restore connection to the exhaust steam supplyand to cut off the auxiliary supply when the pressure of the exhauststeam supply has risen above said minimum, said mechanism including aconnection to said exhaust steam supply, and automatic means forproducing in said connection a pressure below said minimum when thepressure of said exhaust steam supply has risen above a predeterminedmaximum.

4. Thecombination as set forth in claim 3 and in which the means forproducing the low pressure in the connection is constructed andararranged to out 01f the exhaust steam from the ifo automatic mechanismwhen the exhaust steam I the minimum at which such mechanism shuts offthe exhaust steam supply and opens up the auxiliary supply to theinjector.

5. The combination of an apparatus having a normal source of fluidsupply of variable pressure and an auxiliary source of fluid supply andhaving automatic mechanism for shutting off said normal supply and. foropening up said auxiliary supply when the pressure of the normal supplyis below a predetermined minimum and adapted to restore connection tothe normal supply and to cut off the auxiliary supply when the pressureof the normal supply has risen above said minimum, said mechanismincluding a connection to said normal source of supply, and automaticmeans for controlling said automatic mechanism to cause it to shut offsaid normal supply and to open up said auxiliary supply only itsabnormal pressures from said source of a casing in said connection, avalve in said casing adapted when seated to interrupt communicationbetween said source and said apparatus, said casing having a ventaperture, a valve arranged to close said aperture when seated, automaticmeans for holding said vent valve normally closed but adapted to yieldonly to abnormal pressures Within said casing, and means whereby saidfirst mentioned valve closes when said vent valve opens and remains openwhen said vent valve is seated.

' JOSEPH F. GRIFFIN.

